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What is the direction of the net magnetic field at the point?

I'll describe the figure here:

Imagine a cartesian plane.
At (0,y) is a wire carrying a current out of the screen.

At (0, -y)is a wire carrying identical current out of the screen.

At (x, 0) is a point -- so the point is equidistant from the two wires.


I'm confused because if I put my right thumb in direction of the current, and fingers curl in direction of the field, the field is a counterclockwise circle around each wire. But how do I know what is the field at the dot? I feel like it can be either up + up = up, or left + right = 0. But I can't tell which?

There is also an option for not enough information.

  • Physics -

    never mind I got it, I used a compass to figure out the point on the circle to figure out direction


  • Physics -

    Only the B-field components in the y direction will be additive. The x components will cancel at any (x,0)because of symmetry considerations.

    Because of the right-hand rule, the field direction will be +y for x>0 and -y for x<0 (unless I got my hand rules mixed up.)

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